Which all-star event is more exciting?

San Antonio — Tim Duncan spent nearly two decades as the quiet storm in the middle of the San Antonio Spurs franchise, putting the team on his broad shoulders and carrying it to heights unseen in modern American sports.

With Duncan as the focal point, the Spurs won five championships, made the playoffs in all 19 of his seasons and cemented themselves as one of the most successful franchises in all of sports.

And now, the tireless and reluctant superstar is finally calling it a career. The 40-year-old Duncan announced his retirement on Monday, marking the end of an era for the Spurs and the National Basketball Association.

"The greatest power forward ever," the Los Angeles Clippers' Jamal Crawford said Monday, as the tributes to Duncan's career began coming.

Few would dare argue.

Duncan was the No. 1 overall pick in 1997 and teamed with coach Gregg Popovich, point guard Tony Parker and shooting guard Manu Ginobili to turn the Spurs from a solid franchise that could never quite get over the hump into one of the league's superpowers.

The unassuming Duncan won two MVP awards and was one of just four players to be named NBA Finals MVP at least three times. He was a 15-time all-star, a member of the All-NBA first team 10 times and is one of only three players — joining Kareem Abdul-Jabbar and Robert Parrish — to win at least 1,000 games in his career. He is fifth on the NBA's career list in blocks, sixth in rebounds and 14th in scoring.

"The constant staple of their franchise," Cleveland's LeBron James said earlier this year.

Duncan was never one for big endorsement deals or look-at-me news conferences, which is why he was often overshadowed in the public eye by more outsized personalities like the James and Kobe Bryant, who also retired this year after 20 seasons, all with the Los Angeles Lakers. But he leaves this game as one of the league's true giants, perhaps the best power forward to ever play and one who left as indelible a mark on his franchise as any player to come before him.

The announcement comes two months after the Spurs were upset by the Oklahoma City Thunder in the Western Conference semifinals, a six-game exit that immediately had people wondering — yet again — if it was Duncan's last hurrah.

Turns out, it was.

And like everything else Duncan did in his career — aside from win — he retired quietly, with a statement from the team. There will be no victory lap for Duncan, no farewell tour like the one Bryant had this season. Popovich would be available to address Duncan's decision on Tuesday, the Spurs said.

The last time Duncan spoke to reporters was on May 12, when the Spurs had just been eliminated by the Thunder in Game 6 of the Western Conference semifinals. After being ineffective for most of the series, Duncan scored 19 points and teamed with fellow 40-year-old Andre Miller to trim a 26-point lead to nine in the fourth quarter before Russell Westbrook and Kevin Durant closed out the series.

There were hints in that game of Duncan's plans, even though he exercised a contract option later to clear the way for his return. He had always said that he would walk away when he felt he could no longer have a significant impact on the game, and for most of the series the younger Thunder big men had their way with him on the glass.

With the Spurs getting blown out and the fourth quarter set to begin, Popovich and his veteran star had a brief conversation on the bench. Duncan then played all 12 minutes of the fourth quarter without coming out for a rest, perhaps soaking up every second he could in the last game he would ever play. And when the game was over, Duncan waved to the visiting crowd and pointed a finger toward the roof as he headed to the locker room, a rare signal from one of the league's most stoic superstars.

"Timmy's never been a very outspoken or emoting sort of individual on the court," Popovich said earlier this year. "Everybody does it differently."